Blood sampling tubes are widespread and conventionally serve as a sample transporting container, in particular, for taking and preparing blood samples. Blood sampling tubes enable transportation of the withdrawn blood and short-term storage of the withdrawn samples. Similar systems also exist for other bodily fluids, in particular, for urine samples.
Conventionally, there are two different systems that withdraw samples, either by aspiration or by negative pressure. There are tubes with different add-ons in both systems. The design of a blood sampling tube with an aspiration system approximates that of a syringe. By pulling out a plunger, negative pressure that accelerates taking of the fluid is created. By contrast, negative pressure already exists in advance in a blood sampling tube in the case of a blood sampling tube in a negative pressure system. If the blood sampling tube is placed onto an adapter connected to a puncturing cannula, the fluid, in particular blood, is suctioned by the negative pressure present. In both systems, the withdrawn blood may be stabilized for storage or transportation purposes for example by citrate.
In the case of conventional systems, it is necessary to withdraw the withdrawn fluid, (e.g., the withdrawn blood), from the blood sampling tube for further analysis, for example, by pipetting. This procedure has a number of disadvantages. First of all, withdrawing the fluid with the aid of a pipetting device requires a certain amount of manual dexterity on the part of the person taking the sample such that only appropriately educated staff comes into question for this procedure. Furthermore, such a pipetting device for withdrawing the fluid from the blood sampling tube must also be available in situ. This provides that the person wishing to withdraw the blood for analysis purposes has an appropriate pipetting device in situ. However, an in situ device may not always be provided, for example, in a domicile of a patient. Furthermore, withdrawing the fluid from the blood sampling tube is relatively difficult and consumes much time, as a result of which the analysis of the biochemical functions of the withdrawn fluid is delayed.